Process and apparatus for treating mineral oils



Dem-15,1936. M- RFENSKEETAL 2,064,422

PROCESS AND APPARATUS FOR TREATING MINERAL OILS VAPOR 'VAPOR/z5@ /03 Dec. 15, 1936.

M. R. FENSK ET AL 1` yPROCESS AND APPARATUS FOR TREATINGMINERAL OILS ffy 2 llllllllllpl Filed Nov. 9, 1933 VIII/[III 400 illle 'lll/lll. VIII;

llllIIlllIl/Il willlllllllllllllllllllll 2 Sheets-Sheet 2 III/[III] 77 mme -i l f 111111111111. a I a l Patented Dec. 15, 1936 UNITED s'rlt'rlazsv PA'rlgzN'r oFF-Ica aosiszz PROCESS APPARATUS FOR T RAL OILS MINE Merrell R. Fenske and Wilbert B. McCluer, .State ,l

College, Pa., assignors to Pennsylvania Petroleum Research Corporation, a corporation ol Pennsylvania Application November 9, 1933, seria. No. 697,344.' l

SEP 1 01940 iz'claims. (criss-12s) This invention pertains tothe separation .of mixtures of materials. It will be described in connection with the extraction and/or fractionation of mineral oils by the use of solvents.

5 However, it is to be understood `that it is applicable to the separation of mixtures in general.

In copending application Serial No. 10,932, iiled March 13, 1935, by Merrell R. Fenske and Wilbert B. McCiuer, which has matured into Patent 2,037,318, April 14, .1936, is described a process and apparatus adapted for the extraction and/or fractionation o1 mineral oils wherein a plurality ofr liquids of diilerent densities are Vilowed relatively to each other by virtue of diflerenoesin their densities. The types of apparatus described in said copending application employ columns wherein at least one liquid phase is maintained in a widely distributed iorm 2o by causing said relativemovement between said phases to take place in the presence of a group of attenuated packing members arranged in the zone of contact side by side and longitudinally of the ilow ot at least one phase. In practicing said invention with countercurrent tlow, the liquids enter the column at vertically spaced points, vthe feeding points of said liquids being generally' arranged in the order oi their densities with the heaviest liquid being fed atthe top,,although this is not absolutely essential. lAt least one light solution of the liquids is usually taken oil from the column at the top thereof and at least one heavy solution of the liquids is usually taken oi! from the column at the bottom thereof. v

In a more specinc form of said invention.

or moreof the counter-currently flowing liquids is maintained in a plurality 'of separate streams, highly, etlicient contactmeans are provided and/or special means is provided ior the prevention o! channeling ofthe counter-currently ilowing liquids .with or without the setting up oi reilex conditions. i The invention herein-also) rtains to a process wherein a mixture is separated into desired portions by flowing said mixture through acol- -vunm ,relatively to a solvent, the term solvent being employed in a broad sense to include a mixture of compounds and regardless of the efi'ect upon the materials to be separated. In this invention special provision may also be made for` rectiiying or scrubbing the phases while 'in the column. Provision may be also made -in cer- .tain instances for-taking oi! a side stream or side streams of .any or all of the separated portions.

Reilux conditions may be set up by reducing the solvent power of the solvent as it flows through the column. f Reduction in solvent 5 power may be accomplished-either by lowering the temperature or by the addition of a second solvent which acts as a precipitant, or by means oi' removing the solvent'for instance by vaporization. If reduction'insolvent power is accom- 10 plished by lowering the temperature, the ternperature change may be`gradual throughout the length ofthe column or it may be caused to change abruptly at one or more points in the column. The temperature may be reduced in l5- the direction of solvent iiow to. cause reiiux'of oil or in thedirection o! oil flow to cause reiiux o! solvent although lthe former is desired. It

reduction in solvent power is accomplished by the yaddition oLa second solvent which acts as 20 a precipitant, this second solvent may be added v at one point or at a multiplicity of points throughout the length of the column. 'I'he,ad dition of the second solvent at a multiplicity of points throughout the length of the column cor- 25 responding to successive increases in the concentration of the second solvent in the solvent phase in thedirection of solvent iiow is particularly effective. -Reduction in solvent power of any solvent within a column results in continual pre- 30 cipitation of dissolved oil and continual solution of undissolved oil which produces a condition vanalogous to reflux as occurring in distillation that is highly desirable.

obtain the advantages rnot only o! ordinary continuous countercurrent contact but also .the advantages or batch contact and particularly batch` 4 Further features of the invention reside in the construction, arrangement and combinations of parts and in the steps, sequences, and combina- 45 'tions of steps, au or which together with further l.

features will become ,more apparent to'persons f skilledin the art as the specification proceeds vand upon reference to the drawings in which like reference characters have been appended to like 50 parts in the various ilgures. and in which Figure 1 -is a now sheet illustrating the redux action, l

Figure 2 is a sectional elevation ot a further form of the invention, V 55 are fulilled by y Figure 3 is a section on line lar-6a of Figure 2, and

Figure 4 is a sectional elevation shown broken and partly in ilow sheet form.

The. benefits derived from reflux may be evidenced as follows: Figure 1 is a schematic sketch showing a contacting column I, a vaporizer 2, an extract pump 3, a condenser I, a solvent pump 6, a hot circulating medium 6, and a cool circulating medium 1. This gure represents a specific case in which the solvent is heavier than the oil. If, for simplicity, the specific case is assumed in which the colunm is charged with a single appropriate quantity of oil and nlled with solvent which is circulated continually by the arrangement of apparatus as shown in which no products are removed from the system, a condition of total reflux prevails. That is to say, warm fresh solvent continually dissolves oil at the top of the column and reaches a saturation value; the oil whi'ch is dissolved-is that of poorer (or better) lubricating value as defined by viscosity index if the solvent is selective as to type of molecule; this dissolved oil is carried along by the solvent on its downward path through the column: since the column Vis shown as being lagged and hence under adiabatic conditions except for the top and bottom where heat is added and withdrawn respectively, the solvent becomes progressively cooler on its downward path throughjhe column and accordingly progressively. supersaturated with respect to the amountof oil initially dissolved and oil is thrown out of solution orprecipitated continually during the downward course of the solvent; this oil which is precipitated is of progressively lower qualityas more and more oilris precipitated; and this condition produces a quality gradient in the precipitated oil throughout the length of the column; as soon as the small droplets of oil are precipitated they start to rise through the solvent medium in the column since they are lighter than the solvent; lower quality oil in the undissolved state tends to displace higher' quality oil in the dissolved state; hence, during the time interval that the precipitated oil is rising through the column, the lower quality` materials are dissolved by the solvent and higher quality materials are precipitated which in turn start to rise through the column and are dissolved and precipitate still higher quality materials, etc.; the stipulations that no materials are removed from the system and that fresh solvent is continually fed in at the top of the column Dorizins pure solvent from the spent solventcontaining dissolved oill returningthe fresh solvent to the top of the column and recirculating the extract into the lower portion of .hecolumm under these prescribed conditions a vsteady state exists within the column and s. quality gradient of oil is set up and maintained within the column. v

It is evident that in the casein which thel oil is heavier, than the solvent that the systeml need only be reversed in order to carry out a similar effect- It is also evident that a similar can be effected if the solvent powers of the solvent are decreased by the addition of a precipitant as previously mentioned. Under any practical operating condition, it is to remove productjfl either intermittently or, continuously.

described sbove-isopersblstunder either condition' although latter isfpseferred.

' Incontinuous operatiom'fresh oil is-fed into the column st some ons-point or 'atlas multiplicity 4of pointsalthoushitispreferredto feed theoil into a section of the column where the naturally esor may not be returned to the lower part of theA column depending chiefly upon the temperature differential employed between the top and bottom of the column and the solubility of the oil in the solvent employed.

For comparative purposes only, the effect of reflux on increasing the eillciency of any given column in separating lower and higher quality materials from a given quality of feed may be likenedto processing, reprocessing, and reprocessing the original material in columns where reflux is not employed.

The same method of operation and principles apply when the extraction is used to fractionate an oil to produce materials of varying viscosity characteristics instead of varying quality character'istics.

Referring now to Figures 2 and 3, at 65 is shown a column adapted for the alternate engagement and disengagement of phases. It will be noted that column 65 is provided with means for taking off side streams either of oil or of solvent, or of both. Column 65 as shown comprises a plurality of superimposed sections 66, with each adjacent pair of sections 66 being joined by an interposed segregating chamber 61. Any means may be provided for joining the sections 66 and chambers 61 together,such as the flange construction illustrated.

Each section 66 as shown comprises a plurality of tubes which are supported in and project through a pair of spaced plates orfheaders 69 and 10.

' -The upwardly projecting ends 1l of the tubes 68 of the upper section 66 project into v'feeding and segregating .chamber 12, the plate 69 of this section forming the bottom of said chamber 12. The inlet 12 for the heavier liquid is preferably below the upper edges 14 of the ends 1l of tubes 6l, and edges 14 are preferably in a horizontalplane so as to act as weirs for uniformly feeding the heavy liquid into each lof the tubes 6l of the upper section 66.

An outlet 16 is shown for chamber 12 for the withdrawal of light solution.

The tubes 66.of each'of the sections 66 are il-v 'lustrated as being provided with feeding means The feeding means 11 may be of any desired.

construction. That shown is more particularly illustrated in Figure 3 as comprising a main feeder tube I3 having a, plurality of branches 94, each branch communicating with the interior of a tube Il. The flow is illustrated as beingv controlled by metering orifices 96 comprising small tubes of equal lengthand diameter. The purpose of adjusting iiow is to introduce the desired amount of liquid into each of the tubes 6l: yfor the preferred conditions of operation.

The upper-ends 1l of each of the tubes the lower and of the intermediate sections Il project up into a segregating chamber 61, and

,the lower projecting ends 19 of each of the tubes tablished quality gradient is equal to vthat of the il of Il of the upper and `intermediate,sections project downwardly. into afsegregating chamber 1. j i

The um! edges u of ti'sds 1| or tubes u 75 in any chamber 61 are also preferably in the same horizontal plane. The lower edges 88 of the lower ends 19 of each of the tubes 68 of any section 66 are also preferably in a horizontal plane.,

When the tubesl 68 of any two or more s ections are vertically aligned or vertically overlapped, a. cap 8| is preferably interposed between 'any two aligned or overlapping tubes 68 to prevent direct flow of liquid from one tube 68 to the next.

Cap 8| may be'of the'order of a bubble cap 80 and with a pipe 84 preferably below the planev of the edges l11| for purposes which will herein'- after appear.. The ends 19' of the lower section 66 project downwardly into feeding and segregating chamber 85 and each end 19 may be provided with an inverted cap 86 if desired. Any of the other ends 19 may also be provided with inverted caps 86, if. desired, for instance, to increase the number of bubble cap contacts.

Chamber 85 is provided with an inlet l81 for the lighter liquid and an outlet 88 for the heavier solution. x 1

Each .of the sections 66 is provided with a shell 89 which is joined to the flanges of the particular section. Each shell 89 is provided with openings 98 for the ingress and egress of a heat exchange fluid.

Each of the tubes 68 is illustrated as being, packed with a packing 9| which may be of any desired type. Jack chain vfor instance= is found to be very suitable, although any other type of packing may-be employed.

Certain ltypes of packing comprise cardlng teeth, single turn,v double turn, triple turn, or polyturn helixes, open rings, bent carding teeth, H shaped, S shaped, double crossed shaped wire forms, all having dimensions more or less comparable to carding teeth used in the textile industry.

The packing may be supported-in each tube 68 by any suitable means, such as that illustrated at 92,.

However when tubes 68 are of small inner diameter, packing materialsA may not be required.

Tubes 68 may, of course, have a cross section of any desired geometrical conguration but'are.

preferably of sumciently small cross sectional area to avoid serious channeling of the phases through each other. The preferred limiting cross sectional area for each tube 68 will be not only a function of the type of contacting means (if any).`

but also of the manner in which theV contacting means is arranged in each tube, for instance of the degree of uniformity of distribution of packing. Since 4the tubes vmay have sides which are 4straight or indented or of other surface conngura'- tion, the departure of a tube from a straight or continuous form will have its influence. For this reason a definite limit in cross sectional area which, if exceeded insize'. will no longer demonstrate the substantial increase in eiiiciency which we have discovered results from a constriction of It may be stated as a general rule that one yshould proceed with caution aiterexceedinga cross sectional area equivalent to that ofa circui vlar tube in the neighborhood of -two or three inches in diameter although with a proper selection of packing orfother contacting means and a careful distribution in each tube, it may be possible that larger cross sectional areas may be employed while in other cases smaller cross sectional areas may be required.

Therefore, the term relatively small cross sectional area or its equivalent, when employed in this `specification, and in the claims, is intended to mean a cross section which is suiiiciently small because of the constriction of itsarea.

We have obtained highly eicient phase contact Without serious channeling in tubes 'of various cross sectional areas, for instance tubes of circular cross section and of 3A inch, 1 inch, and

of 1.75 inches in diameter. l

Itis simpler to have tubes 68 of any one set of substantially the samecross sectional area and packed in a manner to have substantially the same pressure drop. Thus each phase will substantially equally divide between the tubes. Since. the result of this is to maintain substantially the same proportion of solvent'phase to oil phase in each tube of the set, itfvwill-beobvious, that the tubes 68 of the set may be of different sizes and that the feeding rates may vary according to the difference in perimeters of the tubes and/or adjustments of pressure drop, particularly if substantially the same proportion of phases is maintained in each tube. In other words, the result of having tubes 680i the same size and of main- .to materially increase the contacting eihciency taining uniform feeding conditions for each tube isto cause the rafilnate phase produced by eachtube to be substantially of the same composition -as the raffinate phase produced by any other tubes whether such number be an integer oran fraction.

'I'he column may be operated at any desired pressure. .This pressure may be atmospheric, particularly if the solvents are liquid at atmospheric pressure, or elevated, particularly if this is necessary `to maintain one or more of the solvents in the liquid phase (partially or wholly as desired) while in the column; or reduced, should thisbe part of the solvent or solvents into the vapor phase.u l t In describing the operation of the column 65, it will be assumed that the oil is" heavier than the solvent. Oil may be fed inthrough the opening 18 and if so it will rise about the ends. 1| of tubes 68 ofthe upper section 66 and if the edges .1I are inthe same ,horizontal plane, the oil vwill desirable for any reason, for instance to bring a into the tubes 68 of the latter section 66 and the i undissolved part will flow therefrom down into the next lower chamber61 wherein as in each succeeding section 61 the process of oil collection and redistribution is repeated.

That portion of the oil (if any) which is not dissolved eventually reaches chamber 86 wherein it segregates from the lnilowing fresh solvent andis withdrawn at 88.

Fresh solvent will be fed in through 81 and uniformly up through the tubes 68 of the lower section 66 because of its uniform head at the lower ends of these tubes 68. Caps 86 may be provided over the ends 19 should the bubble cap contact be desired. Otherwise the caps may be removed and, if desired, ends 19 of lower section 66 may be made flush with the plate 19 thereof.

The solvent upon reaching 'the lowermost chamber 61 separates from the down-flowing oil and formsv a layer about the downwardly projecting ends 19 of the tubes 68 of the next higher section 66. Since the edges 88 of the ends 19 are in a horizontal plane, the up-flowing solvent will be equally distributed among the tubes 68 of the latter section 66. Such equal distribution would also take place if the lower edges 80 were ilush with the plate 10 of the respective section.

The solvent continues up through the tubes 68 of this section 66 and is redistributed in like manner in each of the succeeding higher chambers 61.

A counter-current flow of oil and solvent is'thus brought about with th addition of disengagement of phases and redistribution intermediate the ends of the column.

previously referred to might also be fed in at any of the openings 83 or at any of the openings 84 instead of through the means 11. more specifically provided for that purpose. f

If the process is one of solvent extraction, the

side streams of oil will have increasing degrees of improvement from the top to the bottom of the column and the highest degree of improvement will be obtained in theoil withdrawn at 88.

From the foregoing it will be seen thatthis 1 form of the invention may be operated with or without producing reux.

Means have been provided in each of the sections 66 for effecting precipitation of oil from the solvent either by temperature reduction or by adding a precipitating liquid, or both and/or sol--V 'vent-oil solution may be withdrawn at any desired point, concentrated to precipitate oil, which with or without the solvent remaining in the liquid phase, may be returned to the column. The latter is illustrated in Figure 4.

It will, of course, be. understood that a tem- 'perature gradient through the column may also be maintained by feeding the solvent at a higher temperature` than the feeding temperature of,

the oil, or by feeding the oil at a higher .temperature than the feeding temperature of the solvent."

. The former willcause precipitation of oil from solvent andthe latter precipitation of solvent from oil. l

In describing the operation with reflux it will be assumed that the lower section 66 is employed solely for the purposes of effecting solution be'- tween the oilV` and solvent (although precipitation with a corresponding degree of reflux and rectification in this section might take place if de-V sired). f

Ihe up-fiowing solvent when it reaches the lowermost chamber 61 will have a certain amount of voil dissolved therein. If this solvent as it passes up through the tubes 68 of the next higher section 66 is brought to a supersaturated condition either by reduction of temperature, by the addition of a third liquid, and/ or by vaporization of solvent, the excess oil will be precipitated and will flow downwardly into the lowermost chamber 61 and will be fed backinto the tubes 68 of the lowermostsection 66, whereupon a portion will be redissolved, and carried back up for repetition of the cycle, thereby causing rectification in the manner previously' described. )A side stream might be taken oif at the opening 84 Yof the lowermost chamber 61, or at the opening 8 3 thereof, or both as desired.

When the solvent 'reaches the next higher chamber 61, it is redistributed and ows up into the next higher section 66 in which further precipitation might take place causing a reflux of oil back into this chamber 61 and into^the tubes 68 below. One"`or more side streams might be taken off from the latter chamber 61 thesame as from the previous chamber 61. This process may be repeated as many times as desired asI the solvent proceeds up through the column 65 since anynumber of sections 66 may be employed. The

' solventeventually reaches chamber 12 in which it may have a final contact with the inflowing fresh oil if desired by providing caps 94 of the order of b\ubble caps over the upper ends of tubes 68 of the upper section 66. The solvent flows out through opening 16. i

In the above description the fresh oil came in contact with the refluxed oil and of course formed a part of the "side streams taken oil. If ydesired, the side 4streams may comprise solely refluxed oil. This may be accomplished, for instance, by feeding the oil in through the lowermost or next lowermost opening 84,instead of through the openingy 19.

Any one or more of the side streams may be retreated in a separate side tower', for instance, the tower illustrated at |60, which may have any desired construction, for instance, that of any of the towers disclosed herein. The point of feed of the side streams may be governed by any of ,l

the considerations fherein.

It should be particularly noted that the column 65 is not only particularly useful in effecting contact between a plurality of liquids but is also equally ,useful for eilecting contact between a liquid anda vapor or a plurality of vapors. It is, therefore, suitably adapted to distillation or fractionation. In this event, ends 19 of tubes 68 may be ush with their respective plates 10 par- 75 ticularly if sidestreams of vapor are not desired and caps 06 may be removed. Caps 8| and 94 might or might not be'employed as desired'. Such an arrangement will also voperate for solvent treatment purposes since ends 19 are primarily for assistingvthe disengagement of phases and obtainingside streams.

Many variations in constructional form may be resorted to..` For instance, that portion of each tube 88 which falls between plates 69 and 10 of'any section might be dispensed with, in which case the lplates 69 and 10 of each section might remain in place or might be made integral. Openings 90 would be plugged.- The space between plates 69A and 10v of each section 66 might remain empty or it might be partially or completely iillevd with any suitable packing. yAny suitable means might be provided to support the packing, s uch as the plate. 10 or a perforated plate in place of plate 10 or if plate 10 were removed the packing might rest upon the next lower plate 69. In this'event, additional jackets might be provided on each' section for heat exchange purposes and the thirdA liquid might still be fed in through the tubes 11 when desired.

When the oil is lighter than the solventfthe oil may be fed in through '81 Aand withdrawn through opening 16. -Solvent may be fed in' through 11iv and withdrawn at 88.. Side streams of solvent may be withdrawn through the openings 84 and side streams of oil vmay be withdrawn through the openings 83. In lthis event,

the upper section 66 would probably be used exclusively for solution purposes, although not.

necessarily.

If it is not desired to have fth'e fresh oil ow through the refluxed oil, the fresh oil might vbe fed through the upper or any other pipe 83 instead of through the opening 81, and precipitation-might take place further downstream of the solvent flow.

, Many other variations inl operation may be recolumn 85 in a manner so as to reduce the con-- l'It sorted to.

yReferring now more particularly to Figure 4` in' which, for the purposes of. illustration, a portion of column 65 has been reproduced, at |02 is l illustrated a vaporizer which is connected to the centration of solvent in the. column or, in other words, to reduce the solvent power of the solvent in the direction of solvent flow. The manner in which vaporizer |02 'isillustrated as being connected to column 65 4is more particularly adapted for cases in which the solvent is lighter than the oil, since the inlet to the 4 vaporizer I 02 is connected to chamber 61 adjacent its top, that is, at a point within the solvent-oil solution layer in chamber 61.

ln the event that the solvent is heavier than the oil, itis merely necessary to connect the inlet to the vaporizer at a lower point in chamber 61, for instance, adjacent its bottom, for in such cases the solvent-oil solution layer will be on the bottom.

After the solvent-oil solution has been concen-f As mustrad, `both the saturated sowent-o'n solution and the precipitate are so returned. In this case the precipitate will be reuxed down throughA the column and the saturated solventi vrality oi.- compounds.

oil 'solution will continue on upfthrough the col- A condenser |03 is illustrated as being associated with the vaporizer |02 for condensing the solvent vapors, and if desired the `condensed solvent maybe recycled by causing it to enter the column at the same point asthe fresh solvent, or .at'any point above or below the solvent feed plies when precipitation of dissolvedfoilfor reflux purposes-is effected byfa :reduction in temperature of the solvent-oil' solution, and/or by the addition of a "prec'ipitantto the solvent-oil solution. For instance, the vaporiz'er |02 might be substituted by lany suitable receptacle in which the solvent-oilsolution might be cooled and/or4 precipitant added as desired,-or such-a receptacle might be connected in series with the vapori'zer., for` instance, on the downstream side in which` .case any one or more of the foregoing precipitation methods might be used.

Whilethe arrangement shown in Figure 4 is illustrated at a point intermediate the length of column 65,v itis to be understood that it1may be placed at any' desired point including the top .or bottom (depending on the relative density of the solvent) of the column and that it may be connected to the-column in 'any desired manner for thepurposes'y hereinset forth. 1

It is also to be understood that any number of While in the solvent extraction andi/or frac- .tionation processes herein described the solvent and the materials to be treated have been more particularlyl referred to as being in theliquid phase.-l itis to be understood that one or more of' such substances might be wholly or .p artially in the vaporl 0r solid phase wthoutdeparting from ythe spirit oi' the invention.

-It is also .to be understoodthat the inventionv maybe adapted ,to other types of opera-4 tion, fory instance, to one dn which a counter- 0f oil at an intermediate point or with the introduction of different solvents along the line loi' oil flow or along thelinel of solvent flow. Refer-4 ence 'is made to copending application Serial No. 699,050 filed November 21, 1933, which has matured into issued Patent 2,037,319, April 14, 1936.

The solvents may comprise a single or'a plu- When a plurality of compounds are employed, they may' be miscible or partially miscible. Aplurality oi non-miscible solvents might also be employed.-

-such precipitation means may be employed along the column.

`flow of solvents is obtained with the introduction While the invention has been particularly d e- The term solvent in its broader phases includes 'any compound or compounds, whether inthe vapor, liquid and/or solid phase, and regardless of its'infiuence upon the material under treatment.'

lThe relative vdensities of solvents and/or minv eral oils may be obtained upon reference to any standard handbook or by actual measurement.

. from the spirit of the invention. The claims,

therefore, are intended to be limited only as required by the prior art.

We claim 1. In a process for treating a mineral oil with a solvent, the steps of continuously flowing said oil and solvent counter-currently through a contacting column, engaging the counter-currently fiowing oil and solvent phases in a plurality of phase contacting paths of relatively small crosssectional area, and dis'engaging the oil and solvent phases to cause a layer formation thereof intermediate the ends of said c olumn and between disconnected portions of said paths.

2. In a process for contacting liquid phases such as in treating a mineral oil with a'solvent, the steps of continuously flowing said phases countercurrently through a contactingcolumn, engaging the counter-currently flowing phases in a plurality of phase contacting paths of relatively small cross sectional area, and disengaglng the phases to cause at least one layer formation thereof intermediate the ends of said column and between disconnected portions of said paths.

3. In a process for treating a mineral oil with a solvent, the steps of continuously flowing said oil and solvent counter-currently through a contacting column, engaging the-counter-currently flowing oil and solvent phases in a plurality of phase contacting paths of relatively small cross sectional area, and disengaging the oil and solvent phases to cause layer formations thereof at a plurality of spaced points intermediate the ends of said column and between disconnected portions of said paths.

4. In a process for treating a mineral oil with a solvent, the steps of continuously flowing said oil and solvent counter-currently througha contactingcolumn, engaging the counter-currently flowing oil and solvent phases in a plurality of spaced sets of contacting paths ofrelatively small cross sectional area, feeding the solvent and oil phases into, all paths of any one set at substantially the same ratio one to the other, and disengaging the oil and solvent phases between two adjacent sets of paths to cause a layer formation of said phases.

5. In a process for treating a mineral oil with a solvent, the steps of continuously flowing said oil and solvent counter-currently through a contact-s ing column, causing the oil and solvent phases to assume layer formations at a plurality of spaced points intermediate the ends of said column, and removing a part of said oil phase through at least one side stream,'and separatelyv subjecting said side stream to solvent treatment for stripping purposes.

6. In a process for the treatment of a mineral oil with a solvent by counter-currentlyffiowing said oil and solvent through a column and wherein a part of the dissolved oil is precipitated and caused to reux through said column, the steps of precipitating oll from said solvent in a plurality of phase contacting paths of relativelyv small cross sectionalv area, causing the precipitate phase in each path to ow counter-currently to the solvent phase in said path, and causing the solvent and precipitate phases to form at least one layer formation intermediate the ends of the column.

7. In a process for the treatment of a mineral oil with a solvent by counter-currently flowing said oil and solvent through a column and wherein a part of the dissolved oil is precipitated and caused to reflux through said column, the steps of precipitating oil from said solvent in a plurality of phase contacting paths of relatively small cross sectional area, causing the precipitate phase in each path to flow counter-currently to the solvent phase in said path, controlling the precipitation in each path so that the ratio of precipitate phase to solvent phase in said paths will be substantially the same, and causing the solvent and precipitate phases to form at least one layer formation intermediate the ends of the column.

8. In combination, a column, means in said column for causing liquids to flow counter-currently through said column by virtue of a difterence in density such as in the treatment of mineral oils, means in said column for engaging the liquid phases in a plurality of sets of phase contacting paths of relatively small cross sectional area, and means for` disengaging said phases intermediate said sets, and for causing at least one disengaged phase to assume a layer formation. v

9. In a process for treating a mineral oil with a solvent, the steps of flowing said oil and solvent countercurrently and serially through a plurality of spaced sets of phase contacting paths of relatively small cross sectional area, and causing layer formations at opposite ends of each set of phase contacting paths.

10. In a process for treating a mineral oil with a solvent, the steps of flowing said oil and solvent l1. A process for treating a mineral oil with a solvent comprising flowing said-mineral oil and solvent countercurrently through a plurality of.

spaced sets of phase contacting paths of relatively small cross sectional area, precipitating oil from solution in said solvent in at least one set of phase contacting paths to set up reflux conditions, and causing the precipitate thus produced to form at least one layer formation intermediate said sets of phase contacting paths.

12. A process for treating a mineral oil with a solvent comprising flowing said oil and solvent countercurrently through at least one set of phase contacting paths ci' relatively small cross sectional area, flowing the solution of oil in solvent through at least one additional set of phase contacting paths of relatively small cross sectional area, precipitating oil from solution lnsaid solvent in at least one of. said second mentioned sets of phase contacting paths, flowing said precipitate back toward said first mentioned sets of phase contacting paths, and causing said precipitate to i'orm atleast one. layer before returning to said first mentioned set of phase contacting paths.

l MERRELL R. FENSKE.

WILBERT B. MCCLUER.

oleoLAlMER Nn Aprmlqus .FORTREATING MINERAL Onis. 'A Patent dited-'December i v15, 1936'.y :Dlsclalmer filed October 20,1938, by the assignee, Pennsylvania lPetroleum.I Resemch Corpora/tion. v

f 'QHereB-cnterihs disclaimer to claims 1f, 2, 3, 4,.'8, and-'9 of saidlLetters Patent;

I @c :aette November 15, 1938;] 

